Infusions of chemicals into the brain and the development of sustained elevations of blood pressure in the rat.
Osmotic minipumps were used to infuse carbachol chloride (1.23 micrograms/hr), echothiophate iodide (0.5 microgram/hr), histamine dihydrochloride (10 micrograms/hr), prostaglandin E2 (1.0 microgram/hr) and thyrotropin-releasing hormone (0.5 and 5.0 micrograms/hr) solutions into the cerebral ventricles of unanesthetized rats and blood pressure was measured by the tail-cuff method. Histamine dihydrochloride, prostaglandin E2 and thyrotropin-releasing hormone produced an initial rise in blood pressure, but were not effective in producing sustained elevations in blood pressure. Carbachol infusions elevated blood pressure throughout the 7-day infusion period when results were compared to saline-infused animals. Infusions of echothiophate iodide, an anticholinesterase agent, produced an initial rise in blood pressure but these pressor effects were not sustained. In animals infused with echothiophate for 7 days, the pressor response to a challenge dose of echothiophate was diminished.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000187:drug effects*; D002217:Carbachol / Q000494:pharmacology; D003692:Delayed-Action Preparations; D015232:Dinoprostone; D004456:Echothiophate Iodide / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D011458:Prostaglandins E / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology
D003692:Delayed-Action Preparations; D011458:Prostaglandins E; D013973:Thyrotropin-Releasing Hormone; D006632:Histamine; D002217:Carbachol; D004456:Echothiophate Iodide; D015232:Dinoprostone